#658 [security][tools] --offline の外向きの通信を OS の隔離で遮断し、runtime の依存の導入を隔離の中で動かす（第 3 段） - #671

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4, actions/setup-python@v5. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/